Maintenance reliability is, of course, an essential part of any successful business that wants to remain successful. It includes the three PMs: predictive, preventive and proactive maintenance.
The first two, predictive and preventive, can create the third. When predictive and preventive work well together, proactive maintenance is created. PMs tend to be far less expensive than maintenance.
Maintenance costs without PMs are much higher because equipment replacement is usually associated with some form of downtime. It’s an expensive nightmare when lost profits are counted in.
Predictive Maintenance
Predictive maintenance has many different tools available. One very important tool is vibration analysis, which can determine such problems as misalignment, looseness, unbalance and condition of a bearing. These are problems that, when detected in the early stages, can be corrected at an early stage. The smoother a unit can run, the cheaper and longer it will run.
The use of ultrasound is also a very useful tool. It can be used to identify defects in slow turning bearings. Defects can be heard or trended over time. Trending often enables users to predict bearing failures, allowing time to schedule maintenance. From faulty bearings to faulty steam traps, this tool adds value.
Another tool, infrared (IR) cameras, can find hot spots in gearboxes located in remote locations or behind an electrical panel. For example, high pressure, super-heated steam may not be seen with the naked eye, but IR can see it blowing against a bearing seal, thus explaining the source of water buildup in a lubrication system.
These tools, when properly used, are money savers and of high value to a well-established predictive maintenance department.
Preventive Maintenance
Preventive maintenance usually consists of more frequent inspections and are often performed as daily tasks by lubrication technicians.
Daily tasks, such as equipment inspections, may include the following things to look for:
1. Cleanliness
- Unrestricted air flow from cooling fan and fins of motors;
- Oil cooling heat exchangers kept clear of dirt or anything that could block air flow;
- Coupling guards with a viewing window cleaned so strobe light inspections of coupling can take place from time to time;
- Pump power ends and gearboxes since dissipation of heat is essential to extend the life of the lubricant;
- Around breathers because dirt can hold moisture, allowing it to enter through the breather;
- Sight glasses, both level and if equipped with bottom sediment and water bowl (BS&W), to facilitate both level and oil analysis.
2. Adjust oil levels if needed
3. Hydraulic tank filters checked regularly
- Filter may have pop-up buttons or gauges indicating differential pressures
4. Constantly look for leaking oil seals; environment must be protected
- Provide secondary containment.
These are just a few of the many tasks needing attention on a daily basis by lube techs.
Time-based and condition-based monitoring are performed by both preventive and predictive maintenance technicians. The information gathered needs to be shared frequently, if not constantly. The results lead to extended lifecycles of equipment and help eliminate sudden surprises.
Management needs to be notified whenever imminent failures are discovered. Time is often needed to address these upcoming problems. Scheduled shutdowns are most favored; breakdowns in the middle of the night are not.
Here is an example of both departments working and sharing information together:
Vibration analysis has identified a failing bearing on the drive end of a pump. The bearing is beginning to discard filings as it rotates. As a result, wear particles are being released into the oil reservoir. The bearing, the bearing race and the contaminant are getting between the ball and the race, and without filtration, it will create three-body abrasive wear.
The vibration department would naturally create a work order to fix this problem during the next shutdown. If the lubrication department is notified as soon as possible, contaminants can be removed as often as needed.
The goal here is to make it last until the shutdown. A failing bearing could last long enough for that shutdown to take place, but, if three-body wear is left unchecked, time until failure will be greatly reduced and predictions are out the window.
Time until failure often can be accurately predicted if constants can be relied upon. Constants can be established only when good communications between departments is constant.
Proactive Maintenance
Information flowing back and forth between predictive and preventive departments working in harmony creates a proactive maintenance department. This makes management the beneficiary!
